Serial communication isolation circuit

Abstract

The utility model provides a serial communication isolation circuit relates to serial communication technical field, and this circuit includes: protocol conversion module, isolation power module, at least two isolated communication channels, protocol conversion module is used for converting computer interface signal into asynchronous serial communication protocol signal, the input of isolation power module is used for connecting input power supply, and input power supply is the power supply provided for protocol conversion module or is the external input power supply of direct connection, and isolation power module is used for converting input power supply into isolation power supply, isolation communication channel is connected with protocol conversion module, and each isolation communication channel includes: first opto -coupler isolation module and second opto -coupler isolation module, the isolation power input of first opto -coupler isolation module and second opto -coupler isolation module is connected to the output of isolation power module, and isolation power module is used for providing isolation power supply for first opto -coupler isolation module, second opto -coupler isolation module.

Description

Technical Field

[0001] This utility model relates to the field of serial communication technology, specifically a serial communication isolation circuit. Background Technology

[0002] With the rapid development of new energy vehicles, energy storage systems and portable electronic devices, the performance and reliability of the Battery Management System (BMS) are of paramount importance as its core control unit. The Analog Front End (AFE) chip is the core component in the BMS responsible for the high-precision acquisition of key parameters such as battery voltage, current and temperature. The AFE chip requires program burning and data reading operations in the production testing, firmware upgrade and field debugging stages. Based on the consideration of low cost and design simplicity, the industry currently generally adopts the programming scheme based on the Universal Asynchronous Receiver and Transmitter (UART) serial communication protocol.

[0003] In related technologies, current mainstream programming devices generally lack integrated electrical isolation design and can only operate when the battery pack is completely de-energized. If programming or data reading is forcibly performed while the battery pack is energized, dangerous electrical crosstalk will occur between the high-voltage (battery pack terminal voltage, which can reach tens or even hundreds of volts) circuit and the low-voltage (programmer logic circuit, usually 3.3V or 5V) circuit inside the system. This high-low voltage crosstalk can easily cause breakdown and damage to the delicate internal circuit of the AFE chip or the programmer interface, which not only greatly increases the risk of the debugging process, but also significantly increases the equipment maintenance and replacement costs. In addition, conventional equipment lacks multi-channel synchronous operation capability and cannot program or read data from multiple AFE chips at the same time. When dealing with BMS modules that contain multiple batteries connected in series and require multiple AFE chips to work together, debugging and production efficiency are severely restricted. Utility Model Content

[0004] In view of the above problems, this utility model provides a serial communication isolation circuit, which includes: a protocol conversion module, an isolation power supply module, and at least two isolated communication channels;

[0005] The protocol conversion module is used to convert computer interface signals into asynchronous serial communication protocol signals.

[0006] The input terminal of the isolated power supply module is used to connect to an input power source, which is either the power provided by the protocol conversion module or a directly connected external input power source. The isolated power supply module is used to convert the input power source into an isolated power source.

[0007] The isolated communication channel is connected to the protocol conversion module, and each isolated communication channel includes: a first optical coupler isolation module and a second optical coupler isolation module; wherein...

[0008] The signal input terminal of the first optocoupler isolation module is connected to the signal transmitting terminal of the protocol conversion module, the non-isolated power input terminal of the first optocoupler isolation module is connected to the power output terminal of the protocol conversion module, and the signal output terminal of the first optocoupler isolation module is connected to the target device.

[0009] The signal input terminal of the second optocoupler isolation module is connected to the signal transmitting terminal of the target device, the non-isolated power input terminal of the second optocoupler isolation module is connected to the power output terminal of the protocol conversion module, and the signal output terminal of the second optocoupler isolation module is connected to the signal receiving terminal of the protocol conversion module.

[0010] The output terminal of the isolation power supply module is connected to the isolation power input terminals of the first optocoupler isolation module and the second optocoupler isolation module. The isolation power supply module is used to provide isolation power to the first optocoupler isolation module and the second optocoupler isolation module.

[0011] In one possible implementation, the protocol conversion module includes:

[0012] A computer interface unit, the computer interface unit being used to connect to an external computer and obtain input power and communication signals from the computer;

[0013] A protocol conversion chip is connected to the computer interface unit, and the protocol conversion chip is used to parse the signals of the computer interface unit into asynchronous serial communication protocol signals.

[0014] A voltage divider network is connected to the power output terminal of the computer interface unit. The voltage divider network is used to step down the input power supply to the operating voltage required by the protocol conversion chip.

[0015] In one possible implementation, the protocol conversion module further includes a clock circuit, which consists of a crystal oscillator and a matching capacitor connected together, and is used to provide a reference clock signal for the protocol conversion chip.

[0016] In one possible implementation, the protocol conversion module further includes:

[0017] A transmit indicator circuit is provided, which is connected in parallel to the transmit signal line of the protocol conversion chip.

[0018] A receiver indicator circuit is connected in parallel to the receiver signal line of the protocol conversion chip;

[0019] Both the transmitting indicator circuit and the receiving indicator circuit include interconnected current-limiting resistors and light-emitting diodes.

[0020] In one possible implementation, the isolated power supply module includes an isolated converter unit and a linear regulator module;

[0021] The isolation conversion unit is used to isolate and convert the input voltage and output an intermediate DC voltage;

[0022] The input terminal of the linear voltage regulator module is connected to the output terminal of the isolation converter unit. The linear voltage regulator module is used to step down the intermediate DC voltage to a stable isolated low voltage.

[0023] In one possible implementation, the input terminal of the isolation transformation unit is connected to:

[0024] A unidirectional conductive device, wherein the anode of the unidirectional conductive device is connected to the input power supply, and the cathode of the unidirectional conductive device is connected to the isolation conversion unit;

[0025] An input filter capacitor is connected in parallel between the cathode of the unidirectional conductive device and the ground terminal.

[0026] The unidirectional conductive device is used to block reverse current, and the input filter capacitor is used to filter out high-frequency noise.

[0027] In one possible implementation, the linear regulator module includes:

[0028] A reference voltage unit, which is used to generate a stable reference voltage;

[0029] An adjustment transistor unit is provided, wherein the controlled terminal of the adjustment transistor unit is coupled to the reference voltage unit, and the power terminal of the adjustment transistor unit is connected in series between the output terminal of the isolation converter unit and the regulated output terminal.

[0030] In one possible implementation, the linear regulator module further includes:

[0031] A series current limiting network is connected to the input terminal of the linear regulator module and is used to limit the current flowing through the linear regulator module to suppress overcurrent damage.

[0032] A dynamic feedback network includes a filter unit connected in parallel to the regulated output terminal and a phase compensation unit connected across the output circuit. The filter unit is used to suppress low-frequency ripple, and the phase compensation unit is used for phase adjustment.

[0033] In one possible implementation, the first optical coupling isolation module includes:

[0034] A first driving unit, the input of which is connected to the signal transmitting end of the protocol conversion module;

[0035] The first optocoupler unit has its light-emitting input terminal connected to the output terminal of the first driving unit, and its photosensitive output terminal connected to the signal receiving terminal of the target device.

[0036] The first non-isolated power supply node is connected between the power supply terminal of the first drive unit and the input power supply.

[0037] The first isolated power supply node is connected between the photosensitive power supply terminal of the first optocoupler unit and the output terminal of the isolated power supply module.

[0038] The first driving unit is used to convert the signal level of the signal transmitting end of the protocol conversion module into the level required to drive the light-emitting side of the first optocoupler unit.

[0039] In one possible implementation, the second optical coupling isolation module includes:

[0040] The second driving unit has its input terminal connected to the signal transmitting terminal of the target device;

[0041] The second optocoupler unit has its light-emitting input terminal connected to the output terminal of the second driving unit, and its photosensitive output terminal connected to the signal receiving terminal of the protocol conversion module.

[0042] The second isolated power supply node is connected between the power supply terminal of the second drive unit and the output terminal of the isolated power supply module.

[0043] The second non-isolated power supply node is connected between the photosensitive side power supply terminal and the input power supply of the second optocoupler unit.

[0044] The second driving unit is used to convert the signal level of the signal transmitting end of the target device into the level required to drive the light-emitting side of the second optocoupler unit.

[0045] The above-described one or more technical solutions in the embodiments of this application have at least one or more of the following technical effects:

[0046] This utility model provides a serial communication isolation circuit that isolates the transmitting and receiving signal paths through an isolated communication channel. Combined with an isolated power supply module, it provides independent power to the optocoupler isolation side, completely severing the electrical connection between the high-voltage battery circuit and the low-voltage programming circuit, thus eliminating the risk of chip breakdown caused by high-voltage crosstalk during live operation. Furthermore, the circuit has at least two independent isolated communication channels, each containing a complete optocoupler isolation unit. Through a protocol conversion module, it outputs multiple asynchronous serial communication protocol signals in parallel, enabling synchronous programming or data reading of two AFE chips, effectively solving the bottleneck problem of debugging efficiency in multi-AFE systems.

[0047] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, specific embodiments of this utility model are given below. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the module composition structure of the serial communication isolation circuit in an embodiment of this utility model;

[0050] Figure 2 This is a schematic diagram of another module of the serial communication isolation circuit in this embodiment of the present invention.

[0051] Figure 3 This is a schematic diagram of the protocol conversion module circuit of the serial communication isolation circuit in this embodiment of the present invention.

[0052] Figure 4 This is a schematic diagram of the isolation power supply module circuit of the serial communication isolation circuit in this embodiment of the present invention.

[0053] Figure 5 This is a schematic diagram of the circuit principle of one of the isolated communication channels of the serial communication isolation circuit in this embodiment of the present invention.

[0054] Figure 6 This is a schematic diagram of the circuit principle of another isolated communication channel of the serial communication isolation circuit in this embodiment of the present invention.

[0055] Explanation of reference numerals in the attached figures: 100, Protocol conversion module; 110, Computer interface unit; 120, Protocol conversion chip; 130, Voltage divider network; 140, Clock circuit; 150, Transmit indicator circuit; 160, Receive indicator circuit; 200, Isolated power supply module; 210, Isolated converter unit; 220, Linear voltage regulator module; 300, Isolated communication channel; 400, Computer; 500, Target device. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0057] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this invention as detailed in the appended claims.

[0058] The overall concept of the technical solution provided by this utility model is as follows:

[0059] Please see Figure 1 The serial communication isolation circuit includes:

[0060] Protocol conversion module 100, isolated power supply module 200, and at least two isolated communication channels 300;

[0061] The protocol conversion module 100 is used to convert computer interface signals into asynchronous serial communication protocol signals. Computer interface signals refer to signals sent by computer 400 through its interface (such as USB, RS-232, RS-485, etc.). These signals are typically digital signals with specific voltage levels and transmission protocols. Computer interface signals are usually synchronous signals, meaning the sender and receiver transmit data under the control of a clock signal. Asynchronous serial communication protocol signals are a data transmission method where data is transmitted bit by bit in the form of a bit stream. Each character consists of a start bit, data bits, parity bits, and stop bits. Common asynchronous serial communication protocols include UART (Universal Asynchronous Receiver / Transmitter), RS-232, and RS-485. Assuming computer 400 sends data via a USB interface, the protocol conversion module 100 converts the computer 400's USB interface signal into a TTL-level serial port signal, which is then transmitted to the target device 500 through the isolated communication channel 300. In this way, the target device 500 can receive and send data via the TTL serial port interface without directly supporting the USB protocol.

[0062] The input terminal of the isolated power supply module 200 is used to connect to an input power source, which may be the power provided by the protocol conversion module 100 or a directly connected external input power source. The isolated power supply module 200 is used to convert the input power source into an isolated power source. Specifically, in some cases, the protocol conversion module 100 has integrated power management functions and can provide power to the entire system. In this case, the input terminal of the isolated power supply module 200 is connected to the power output provided by the protocol conversion module 100. Alternatively, in other cases, the system may require external power supply. In this case, the input terminal of the isolated power supply module 200 is directly connected to an external power source, such as an AC power adapter or a battery. The isolated power supply module 200 is mainly used to convert the input power source into an isolated power source to ensure electrical isolation between different parts of the entire system, thereby improving the system's safety and anti-interference capability. As needed, the isolated power supply module 200 can also perform voltage conversion, such as converting high voltage to low voltage or low voltage to high voltage, to meet the power requirements of different modules.

[0063] The isolated communication channel 300 is connected to the protocol conversion module 100. Each isolated communication channel 300 includes: a first optical coupler isolation module and a second optical coupler isolation module; wherein...

[0064] The signal input terminal of the first optocoupler isolation module is connected to the signal transmitting terminal of the protocol conversion module 100, the non-isolated power input terminal of the first optocoupler isolation module is connected to the power output terminal of the protocol conversion module 100, and the signal output terminal of the first optocoupler isolation module is connected to the target device 500. The first optocoupler isolation module is responsible for transmitting the signal from the protocol conversion module 100 to the target device 500, while realizing the electrical isolation of the signal. For example, the first optocoupler isolation module receives the TTL serial port signal from the protocol conversion module 100, then converts the electrical signal into an optical signal through optocoupler technology, then converts the optical signal back into an electrical signal to realize the electrical isolation of the signal, and finally transmits the isolated signal to the target device 500.

[0065] The signal input terminal of the second optocoupler isolation module is connected to the signal transmitting terminal of the target device 500, the non-isolated power input terminal of the second optocoupler isolation module is connected to the power output terminal of the protocol conversion module 100, and the signal output terminal of the second optocoupler isolation module is connected to the signal receiving terminal of the protocol conversion module 100. The second optocoupler isolation module is responsible for realizing the signal transmission from the target device 500 to the protocol conversion module 100, while ensuring the electrical isolation of the signal. For example, the signal input terminal of the second optocoupler isolation module receives TTL serial port signals from the target device 500. These signals contain data information sent by the target device 500. Then, through optocoupler technology, the electrical signal is converted into an optical signal, and then the optical signal is converted back into an electrical signal. This optical-electrical-optical conversion process realizes the electrical isolation of the signal, preventing the influence of electrical interference and voltage spikes on the signal. The isolated signal is transmitted to the signal receiving terminal of the protocol conversion module 100 through the signal output terminal. The protocol conversion module 100 further processes the received signal, such as converting it into a USB signal or other form of signal, so that the computer 400 can process it.

[0066] The output terminal of the isolation power supply module 200 is connected to the isolation power input terminal of the first optocoupler isolation module and the second optocoupler isolation module. The isolation power supply module 200 is used to provide isolation power to the first optocoupler isolation module and the second optocoupler isolation module. Through the isolation power supply module 200, electrical isolation is achieved between the input power supply and the optocoupler isolation module, which improves the safety of signal transmission.

[0067] The circuit isolates the transmitting and receiving signal paths through the isolation communication channel 300, and provides independent power supply to the optocoupler isolation side in conjunction with the isolation power supply module 200. This completely cuts off the electrical connection between the high-voltage battery circuit and the low-voltage programming circuit, eliminating the risk of chip breakdown caused by high-voltage crosstalk during live operation. In addition, the circuit has at least two independent isolation communication channels 300, each containing a complete optocoupler isolation unit. Through the protocol conversion module 100, multiple asynchronous serial communication protocol signals are output in parallel, enabling synchronous programming or data reading of two AFE chips, effectively solving the bottleneck problem of debugging efficiency in multi-AFE systems.

[0068] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0069] Please see Figure 3 The protocol conversion module 100 includes:

[0070] Computer interface unit 110 is used to connect to an external computer 400 and obtain input power and communication signals from the computer 400. Computer interface unit 110 typically supports a variety of common computer interfaces, such as USB, RS-232, RS-485, Ethernet, etc., depending on the design requirements.

[0071] Protocol conversion chip 120 is connected to computer interface unit 110. Protocol conversion chip 120 is used to parse the signals of computer interface unit 110 into asynchronous serial communication protocol signals. The input terminal of protocol conversion chip 120 is connected to the signal output terminal of computer interface unit 110, and the power supply terminal of protocol conversion chip 120 is connected to the power output terminal of computer interface unit 110 to obtain power supply. For example, the protocol conversion chip can be a CH340G conversion chip U7. CH340G is a commonly used USB to serial port chip that supports USB to UART, USB to RS-232 and other functions.

[0072] Voltage divider network 130, connected to the power output of computer interface unit 110, is used to step down the input power supply to the operating voltage required by protocol conversion chip 120. Voltage divider network 130 receives input power from computer 400 (e.g., 5V power provided by USB interface), and then reduces the voltage of the input power supply to the operating voltage required by protocol conversion chip 120 (e.g., stepping down 5V to 3.3V or lower, depending on the chip's requirements). Figure 3 As shown, the voltage divider network 130 consists of diodes D2 and D3 connected in series. Utilizing the principle of resistor voltage division, the input voltage can be reduced to the required operating voltage through two or more resistors connected in series. The voltage divider network 130 reduces the input power supply to the operating voltage required by the protocol conversion chip 120, ensuring the normal operation of the chip.

[0073] Assuming the protocol conversion chip 120 operates at 3.3V and the input power supply is 5V, please refer to [link / reference]. Figure 3The circuit input receives 5V power from the computer 400 via the computer interface unit 110. After being stepped down by the voltage divider network 130 composed of diodes D2 and D3, a stable 3.3V voltage is generated to provide operating power for the conversion chip U7. Simultaneously, the original 5V power supply can be directly connected to the CON1 interface without being stepped down, thus enabling the entire circuit system to simultaneously provide both 3.3V and 5V dual power output capabilities. Resistor R21 and LED D14 form the power on / off indicator circuit for the conversion chip U7. When the 5V power supply is connected, LED D14 conducts, indicating that the 5V power supply is on and the circuit is in operation.

[0074] Please see Figure 3 The protocol conversion module 100 also includes a clock circuit 140, which is composed of a crystal oscillator and a matching capacitor. The clock circuit 140 is used to provide a reference clock signal for the protocol conversion chip 120. Figure 3 As shown, the crystal oscillator includes crystal oscillator U5, and matching capacitors include capacitors C7 and C9. Pin 1 of crystal oscillator U5 is connected to the clock input pin of conversion chip U7, and pin 2 of crystal oscillator U5 is connected to ground. Capacitor C7 is connected to one pin of crystal oscillator U5 and ground, and capacitor C9 is connected to the other pin of crystal oscillator U5 and ground. When the circuit is powered on, crystal oscillator U5 starts to oscillate under the action of matching capacitors C7 and C9, generating a stable oscillation frequency. The oscillation circuit inside conversion chip U7 amplifies and shapes the signal generated by crystal oscillator U5 to generate a stable clock signal. The generated clock signal is provided to various functional modules of conversion chip U7 as its reference clock. Optionally, crystal oscillator U5 can be an X322512MOB4SI oscillator. The X322512MOB4SI oscillator has the advantages of high precision, wide temperature range and low power consumption, and is suitable for various applications that require a stable clock signal.

[0075] Please see Figure 3 The protocol conversion module 100 also includes:

[0076] Transmit indicator circuit 150 is connected in parallel to the transmit signal line of protocol conversion chip 120; when protocol conversion chip 120 transmits data, transmit indicator circuit 150 will indicate that data is being transmitted.

[0077] The receive indicator circuit 160 is connected in parallel to the receive signal line of the protocol conversion chip 120; when the protocol conversion chip 120 receives data, the receive indicator circuit 160 will indicate that data is being received.

[0078] Both the transmit indicator circuit 150 and the receive indicator circuit 160 include interconnected current-limiting resistors and light-emitting diodes; such as Figure 3 In the transmission indicator circuit 150, a resistor R16 and a light-emitting diode D4 are connected in series. The reception indicator circuit 160 includes a resistor R4 and a diode D5 connected in series. When the conversion chip U7 transmits data, the voltage on the transmission signal line changes. Since the transmission indicator circuit 150 is connected in parallel to the transmission signal line, the voltage change causes the light-emitting diode D4 to conduct, and the light-emitting diode D4 emits visible light. Similarly, when the protocol conversion chip 120 transmits data, the voltage change causes the light-emitting diode D5 to conduct, and the light-emitting diode D5 emits visible light. The on / off state of the light-emitting diodes provides users with intuitive feedback on the communication status.

[0079] Please see Figure 2 The isolated power supply module 200 includes an isolated converter unit 210 and a linear regulator module 220;

[0080] The isolation conversion unit 210 is used to isolate and convert the input voltage and output an intermediate DC voltage. The isolation conversion unit 210 receives the voltage from the input power supply, converts the input voltage to another voltage level, and achieves electrical isolation. The specific voltage value of the intermediate DC voltage depends on the design requirements.

[0081] The input terminal of the linear voltage regulator module 220 is connected to the output terminal of the isolation converter unit 210. The linear voltage regulator module 220 is used to step down the intermediate DC voltage to a stable isolated low voltage. The linear voltage regulator module 220 steps down the intermediate DC voltage output by the isolation converter unit 210 to a stable isolated low voltage, providing a stable power supply. The core function of the linear voltage regulator circuit is to step down the voltage and act as a load, preventing the actual power of the load on the isolation converter unit 210 from being less than 10% of the rated output power, which would lead to voltage instability.

[0082] Please see Figure 4 The input terminals of the isolation converter unit 210 are connected to:

[0083] A unidirectional conductive device, the anode of which is connected to the input power supply, and the cathode of which is connected to the isolation conversion unit 210.

[0084] An input filter capacitor is connected in parallel between the cathode of the unidirectional conductive device and the ground terminal.

[0085] The unidirectional conductive device is used to block reverse current, and the input filter capacitor is used to filter out high-frequency noise. For example, the isolation converter unit 210 includes an isolation converter chip U2, and the unidirectional conductive device includes a reverse protection diode D1. The anode of the reverse protection diode D1 is connected to the input power supply, and the cathode is connected to the input terminal of the isolation converter chip U2. The reverse protection diode D1 prevents the input voltage from reversing and protects the circuit. The input filter capacitor includes a capacitor C14. One end of the capacitor C14 is connected to the cathode of the reverse protection diode D1, and the other end is connected to ground. The capacitor C14 is used to filter out high-frequency noise in the input power supply and improve power quality.

[0086] Please see Figure 4 The linear regulator module 220 includes:

[0087] The reference voltage unit is used to generate a stable reference voltage; a commonly used reference voltage source is a Zener diode, which can provide a stable voltage drop under reverse breakdown voltage.

[0088] The adjusting transistor unit has its controlled terminal coupled to the reference voltage unit, and its power terminal connected in series between the output terminal of the isolation converter unit 210 and the regulated output terminal. The adjusting transistor unit is used to dynamically adjust the output voltage based on the reference voltage provided by the reference voltage unit.

[0089] For example, please refer to Figure 4 The reference voltage unit includes a voltage reference chip ZD1, which provides a stable reference voltage to control the conduction state of transistor Q5, thereby regulating the output voltage. The adjusting transistor unit includes transistor Q5, which dynamically adjusts the output voltage based on the reference voltage provided by the voltage reference chip ZD1. Resistors R6 and R7 form a voltage divider, which divides the reference voltage and provides it to the base of transistor Q5. The voltage after voltage division determines the conduction level of transistor Q5, thus controlling the output voltage.

[0090] Furthermore, the linear regulator module 220 also includes:

[0091] A series current limiting network is connected to the input terminal of the linear regulator module 220 and is used to limit the current flowing through the linear regulator module 220 to suppress overcurrent damage. By setting a series current limiting network in the circuit, damage to circuit components or system failure caused by excessive current can be prevented. For example, please refer to... Figure 4 The series current limiting network includes current limiting resistors R1 and R3, which are connected in series in the power supply line to limit the current flowing through ZD1, thereby protecting the voltage reference chip ZD1 and preventing excessive current from damaging the chip.

[0092] The dynamic feedback network includes a filter unit connected in parallel to the regulated output terminal and a phase compensation unit connected across the output circuit. The filter unit is used to suppress low-frequency ripple, and the phase compensation unit is used for phase adjustment. For example, the dynamic feedback network includes filter capacitors C1 and C4 connected in parallel to the regulated output terminal. Filter capacitors C1 and C4 are used to suppress low-frequency ripple and stabilize the output DC voltage. The phase compensation unit includes a feedback capacitor C5. One end of the feedback capacitor C5 is connected to the base of transistor Q5, and the other end is connected to the regulated output terminal. The feedback capacitor C5 feeds a portion of the output voltage back to the base of transistor Q5, forming a negative feedback loop. At low frequencies, the feedback capacitor C5 presents high impedance, allowing low-frequency feedback signals to pass through and ensuring the circuit's response to low-frequency changes. At high frequencies, the feedback capacitor C5 presents low impedance, and the high-frequency feedback signal bypasses to ground through the feedback capacitor C5. This high-frequency bypass effect changes the phase of the feedback signal and prevents self-oscillation caused by high-frequency signals.

[0093] Please see Figure 5 and Figure 6 There are two isolated communication channels 300. Figure 5 This is a schematic diagram of the circuit principle of one of the isolated communication channels 300. Figure 6 The circuit diagram for another isolated communication channel 300 is shown below. The electronic components of both isolated communication channels 300 are identical. Each isolated communication channel 300 includes a first optocoupler module and a second optocoupler module. (The following text refers to...) Figure 5 The circuit diagram of the isolated communication channel 300 described herein will be explained in detail. Figure 6 The principle and Figure 5 Consistent, please refer to Figure 5 ,

[0094] The first optocoupler isolation module includes:

[0095] The first driving unit has its input terminal connected to the signal transmitting terminal of the protocol conversion module 100. The first driving unit is used to convert the signal level of the signal transmitting terminal of the protocol conversion module 100 into the level required to drive the light-emitting side of the first optocoupler unit. It provides sufficient current driving capability to ensure that the light-emitting side of the optocoupler unit can work normally. For example, the first driving unit includes a transistor Q1. The base of the transistor Q1 is connected to the signal transmitting terminal TXD of the protocol conversion module 100, the emitter of the transistor Q1 is connected to the first optocoupler unit, and the collector of the transistor Q1 is grounded.

[0096] The first optocoupler unit has its light-emitting input connected to the output of the first driving unit, and its photosensitive output connected to the signal receiving end of the target device 500. The first optocoupler unit converts the electrical signal output by the first driving unit into an optical signal, and then converts the optical signal back into an electrical signal, transmitting it to the signal receiving end of the target device 500. Through the optocoupler element, electrical isolation between the signal transmitting end and the receiving end is achieved, preventing electrical interference and voltage spikes. For example, the first optocoupler unit includes optocoupler OP1, whose light-emitting cathode is connected to the emitter of transistor Q1. When the signal transmitting end TXD is high, transistor Q1 is cut off, and the photosensitive side of optocoupler OP1 outputs an isolated high-level signal. When the transmitting end TXD is low, transistor Q1 is turned on, and the photosensitive side of optocoupler OP1 outputs an isolated low-level signal, resulting in an isolated in-phase TXD signal.

[0097] The first non-isolated power supply node is connected between the power supply terminal of the first drive unit and the input power supply. The first non-isolated power supply node is used to provide power to the first drive unit. The power supply connected to this node is a non-isolated power supply, that is, it is directly connected to the input power supply (VCC5V in the figure).

[0098] The first isolated power supply node is connected between the photosensitive side power supply terminal of the first optocoupler unit and the output terminal of the isolated power supply module 200. The first isolated power supply node provides power to the photosensitive side of the first optocoupler unit. The power supply connected to this node is an isolated power supply (5V-ISO in the figure), that is, through the power supply provided by the isolated power supply module 200, electrical isolation from the input power supply is achieved.

[0099] The second optocoupler isolation module includes:

[0100] The second driving unit has its input terminal connected to the signal transmitting terminal of the target device 500. The second driving unit is used to convert the signal level of the signal transmitting terminal of the target device 500 into the level required to drive the light-emitting side of the second optocoupler unit. It provides sufficient current driving capability to ensure that the light-emitting side of the optocoupler unit can work normally. For example, the second driving unit includes a transistor Q2. The base of the transistor Q2 is connected to the signal transmitting terminal TXD-ISO1 of the target device 500, the emitter of the transistor Q1 is connected to the second optocoupler unit, and the collector of the transistor Q1 is grounded.

[0101] The second optocoupler unit has its light-emitting input connected to the output of the second driving unit, and its photosensitive output connected to the signal receiving end of the protocol conversion module 100. The second optocoupler unit converts the electrical signal output by the second driving unit into an optical signal, and then converts the optical signal back into an electrical signal, transmitting it to the signal receiving end of the protocol conversion module 100. Through the optocoupler element, electrical isolation between the signal transmitting end and the receiving end is achieved, preventing electrical interference and voltage spikes. For example, the second optocoupler unit includes optocoupler OP2, whose light-emitting cathode is connected to the emitter of transistor Q2. When the signal transmitting end TXD-ISO1 is high, transistor Q2 is cut off, and the photosensitive side of optocoupler OP2 outputs an isolated high-level signal. When the signal transmitting end TXD-ISO1 is low, transistor Q2 is turned on, and the photosensitive side of optocoupler OP2 outputs an isolated low-level signal, resulting in an isolated in-phase TXD signal.

[0102] The second isolated power supply node is connected between the power supply terminal of the second drive unit and the output terminal of the isolated power supply module 200; the second non-isolated power supply node is used to provide power to the second drive unit. The power supply connected to this node is a non-isolated power supply, that is, it is directly connected to the input power supply (VCC5V in the figure).

[0103] The second non-isolated power supply node is connected between the photosensitive side power supply terminal of the second optocoupler unit and the input power supply; the second isolated power supply node provides power to the photosensitive side of the second optocoupler unit. The power supply connected to this node is an isolated power supply (5V-ISO in the figure), that is, the power supply provided by the isolated power supply module 200 achieves electrical isolation from the input power supply.

[0104] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0105] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this utility model without departing from the spirit and scope of the embodiments of this utility model. Therefore, if these modifications and variations to the embodiments of this utility model fall within the scope of the claims of this utility model and their equivalents, then this utility model also intends to include these modifications and variations.

Claims

1. A serial communication isolation circuit, characterized in that, include: Protocol conversion module, isolated power supply module, and at least two isolated communication channels; The protocol conversion module is used to convert computer interface signals into asynchronous serial communication protocol signals. The input terminal of the isolated power supply module is used to connect to an input power source, which is either the power provided by the protocol conversion module or a directly connected external input power source. The isolated power supply module is used to convert the input power source into an isolated power source. The isolated communication channel is connected to the protocol conversion module, and each isolated communication channel includes: a first optical coupler isolation module and a second optical coupler isolation module; wherein... The signal input terminal of the first optocoupler isolation module is connected to the signal transmitting terminal of the protocol conversion module, the non-isolated power input terminal of the first optocoupler isolation module is connected to the power output terminal of the protocol conversion module, and the signal output terminal of the first optocoupler isolation module is connected to the target device. The signal input terminal of the second optocoupler isolation module is connected to the signal transmitting terminal of the target device, the non-isolated power input terminal of the second optocoupler isolation module is connected to the power output terminal of the protocol conversion module, and the signal output terminal of the second optocoupler isolation module is connected to the signal receiving terminal of the protocol conversion module. The output terminal of the isolation power supply module is connected to the isolation power input terminals of the first optocoupler isolation module and the second optocoupler isolation module. The isolation power supply module is used to provide isolation power to the first optocoupler isolation module and the second optocoupler isolation module.

2. The serial communication isolation circuit according to claim 1, characterized in that, The protocol conversion module includes: A computer interface unit, the computer interface unit being used to connect to an external computer and obtain input power and communication signals from the computer; A protocol conversion chip is connected to the computer interface unit, and the protocol conversion chip is used to parse the signals of the computer interface unit into asynchronous serial communication protocol signals. A voltage divider network is connected to the power output terminal of the computer interface unit. The voltage divider network is used to step down the input power supply to the operating voltage required by the protocol conversion chip.

3. The serial communication isolation circuit according to claim 2, characterized in that, The protocol conversion module also includes a clock circuit, which is composed of a crystal oscillator and a matching capacitor. The clock circuit is used to provide a reference clock signal for the protocol conversion chip.

4. A serial communication isolation circuit according to claim 2, characterized in that, The protocol conversion module also includes: A transmit indicator circuit is provided, which is connected in parallel to the transmit signal line of the protocol conversion chip. A receiver indicator circuit is connected in parallel to the receiver signal line of the protocol conversion chip; Both the transmitting indicator circuit and the receiving indicator circuit include interconnected current-limiting resistors and light-emitting diodes.

5. A serial communication isolation circuit according to claim 1, characterized in that, The isolated power supply module includes an isolated converter unit and a linear voltage regulator module; The isolation conversion unit is used to isolate and convert the input voltage and output an intermediate DC voltage; The input terminal of the linear voltage regulator module is connected to the output terminal of the isolation converter unit. The linear voltage regulator module is used to step down the intermediate DC voltage to a stable isolated low voltage.

6. A serial communication isolation circuit according to claim 5, characterized in that, The input terminal of the isolation converter unit is connected to: A unidirectional conductive device, wherein the anode of the unidirectional conductive device is connected to the input power supply, and the cathode of the unidirectional conductive device is connected to the isolation conversion unit; An input filter capacitor is connected in parallel between the cathode of the unidirectional conductive device and the ground terminal. The unidirectional conductive device is used to block reverse current, and the input filter capacitor is used to filter out high-frequency noise.

7. A serial communication isolation circuit according to claim 5, characterized in that, The linear voltage regulator module includes: A reference voltage unit, which is used to generate a stable reference voltage; An adjustment transistor unit is provided, wherein the controlled terminal of the adjustment transistor unit is coupled to the reference voltage unit, and the power terminal of the adjustment transistor unit is connected in series between the output terminal of the isolation converter unit and the regulated output terminal.

8. A serial communication isolation circuit according to claim 7, characterized in that, The linear voltage regulator module also includes: A series current limiting network is connected to the input terminal of the linear regulator module and is used to limit the current flowing through the linear regulator module to suppress overcurrent damage. A dynamic feedback network includes a filter unit connected in parallel to the regulated output terminal and a phase compensation unit connected across the output circuit. The filter unit is used to suppress low-frequency ripple, and the phase compensation unit is used for phase adjustment.

9. A serial communication isolation circuit according to claim 1, characterized in that, The first optical isolation module includes: A first driving unit, the input of which is connected to the signal transmitting end of the protocol conversion module; The first optocoupler unit has its light-emitting input terminal connected to the output terminal of the first driving unit, and its photosensitive output terminal connected to the signal receiving terminal of the target device. The first non-isolated power supply node is connected between the power supply terminal of the first drive unit and the input power supply. The first isolated power supply node is connected between the photosensitive power supply terminal of the first optocoupler unit and the output terminal of the isolated power supply module. The first driving unit is used to convert the signal level of the signal transmitting end of the protocol conversion module into the level required to drive the light-emitting side of the first optocoupler unit.

10. A serial communication isolation circuit according to claim 9, characterized in that, The second optocoupler isolation module includes: The second driving unit has its input terminal connected to the signal transmitting terminal of the target device; The second optocoupler unit has its light-emitting input terminal connected to the output terminal of the second driving unit, and its photosensitive output terminal connected to the signal receiving terminal of the protocol conversion module. The second isolated power supply node is connected between the power supply terminal of the second drive unit and the output terminal of the isolated power supply module. The second non-isolated power supply node is connected between the photosensitive side power supply terminal and the input power supply of the second optocoupler unit. The second driving unit is used to convert the signal level of the signal transmitting end of the target device into the level required to drive the light-emitting side of the second optocoupler unit.

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